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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: set ts=8 sts=2 et sw=2 tw=80:
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef util_PolicyAllocator_h
#define util_PolicyAllocator_h
#include "js/Utility.h"
namespace js {
// Adapts an AllocPolicy into a C++ standard allocator, suitable for use in STL
// containers. These containers don't support OOM handling, so this allocator
// will crash on OOM.
//
// Note: this requires the allocator to overload operator==. This should return
// true only if the storage allocated by one allocator can be deallocated
// through another. This is always the case for stateless allocators.
template <typename T, typename AllocPolicy>
struct PolicyAllocator : private AllocPolicy {
using value_type = T;
using size_type = std::size_t;
using difference_type = std::ptrdiff_t;
template <typename U, typename AP>
friend struct PolicyAllocator;
explicit PolicyAllocator(const AllocPolicy& policy) : AllocPolicy(policy) {}
template <typename U>
explicit PolicyAllocator(const PolicyAllocator<U, AllocPolicy>& other)
: AllocPolicy(other) {}
T* allocate(size_t n) {
js::AutoEnterOOMUnsafeRegion oomUnsafe;
T* result = this->template pod_malloc<T>(n);
if (MOZ_UNLIKELY(!result)) {
oomUnsafe.crash("PolicyAllocator::allocate");
}
return result;
}
void deallocate(T* p, size_t n) { this->free_(p, n); }
template <class U>
struct rebind {
using other = PolicyAllocator<U, AllocPolicy>;
};
const AllocPolicy& allocPolicy() const { return *this; }
template <typename U>
bool operator==(const PolicyAllocator<U, AllocPolicy>& other) const {
return allocPolicy() == other.allocPolicy();
}
};
} /* namespace js */
#endif /* util_PolicyAllocator_h */